July 2018
Volume 59, Issue 9
Open Access
ARVO Annual Meeting Abstract  |   July 2018
In Vivo Measurement of the Human Crystalline Lens Equivalent Refractive Index using Whole-eye OCT
Author Affiliations & Notes
  • Gabrielle Mesquita
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
    Department of Biomedical Engineering, University of Miami College of Engineering , Coral Gables, Florida, United States
  • Yu-Cherng Chang
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
    Department of Biomedical Engineering, University of Miami College of Engineering , Coral Gables, Florida, United States
  • Florence Cabot
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
    Anne Bates Leach Eye Hospital , Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Siobhan Williams
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
    Department of Biomedical Engineering, University of Miami College of Engineering , Coral Gables, Florida, United States
  • Giovanni Gregori
    Quantitative Imaging Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Arthur Ho
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
    Brien Holden Vision Institute , Sydney, New South Wales, Australia
  • Marco Ruggeri
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Sonia H Yoo
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
    Anne Bates Leach Eye Hospital , Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Jean-Marie A Parel
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
    Vision Cooperative Research , Sydney, New South Wales, Australia
  • Fabrice Manns
    Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
    Department of Biomedical Engineering, University of Miami College of Engineering , Coral Gables, Florida, United States
  • Footnotes
    Commercial Relationships   Gabrielle Mesquita, None; Yu-Cherng Chang, None; Florence Cabot, None; Siobhan Williams, None; Giovanni Gregori, None; Arthur Ho, None; Marco Ruggeri, US Patent 8,425,037 (P); Sonia Yoo, None; Jean-Marie Parel, US Patent 8,425,037 (P); Fabrice Manns, US Patent 8,425,037 (P)
  • Footnotes
    Support  National Eye Institute Grants 1F30EY027162 1R01EY021834, P30EY14801 (Center Grant); Florida Lions Eye Bank; Drs KR Olsen and ME Hildebrandt, Drs R Urs and A Furtado; the Henri and Flore Lesieur Foundation (JMP); an unrestricted grant from Research to Prevent Blindness; and the Australian Federal Government Cooperative Research Centre Scheme through the Vision Cooperative Research Center.
Investigative Ophthalmology & Visual Science July 2018, Vol.59, 2979. doi:
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    • Get Citation

      Gabrielle Mesquita, Yu-Cherng Chang, Florence Cabot, Siobhan Williams, Giovanni Gregori, Arthur Ho, Marco Ruggeri, Sonia H Yoo, Jean-Marie A Parel, Fabrice Manns; In Vivo Measurement of the Human Crystalline Lens Equivalent Refractive Index using Whole-eye OCT. Invest. Ophthalmol. Vis. Sci. 2018;59(9):2979.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Knowledge of the equivalent index of the lens and its age-dependence can provide insight into age-related changes in the lens refractive index (RI) distribution. Calculating the equivalent RI generally requires the use of multiple biometry devices which increases measurement uncertainty. The purpose of this study is to evaluate the feasibility of determining the equivalent index in vivo using a single OCT system that generates images of the whole eye.

Methods : Following an IRB-approved protocol, the left eye of 8 subjects (40.1 ± 14.8 years old, spherical equivalent refraction ranging from -3 to 0 D) was imaged in the unaccommodated state using a custom-built extended depth OCT imaging system with an axial resolution of 8 µm. The system generates cross-sectional images consisting of 400 A-lines, ranging in depth from the cornea to the retina and at a rate of 8.7 frames per second (Ruggeri et al, Biomed Opt Express 3:1506-1520; 2012). Boundaries of the cornea, lens, and retina were automatically segmented from the OCT images. Central corneal thickness, anterior chamber depth, lens thickness, vitreous chamber depth, and anterior and posterior corneal and lens curvature were calculated from the segmentation data (Fig 1). Using a method based on Scheimpflug imaging (Dubbelman et al, Vision Research 41:1867-1877; 2001), an optimal equivalent RI was determined for each subject that minimized the error between the manifest spherical equivalent refraction and the refraction calculated using an eye model based on the data from biometry.

Results : The measured equivalent RI values ranged from 1.395 to 1.440 with a mean value of 1.415 ± 0.016, across subjects. The equivalent RI decreased with age (RI = -0.0008*age + 1.4467, p = 0.048) (Fig 2). The values attained and relationship between the equivalent RI and age are in agreement with the findings previously published by Dubbelman.

Conclusions : The study demonstrates the feasibility of quantifying the crystalline lens equivalent RI from in vivo OCT images.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Fig 1: Whole eye OCT image. Ocular distances of the subjects and ocular surface curvatures for the anterior and posterior cornea, and anterior and posterior lens were measured from OCT images.

Fig 1: Whole eye OCT image. Ocular distances of the subjects and ocular surface curvatures for the anterior and posterior cornea, and anterior and posterior lens were measured from OCT images.

 

Fig 2: Equivalent refractive index as a function of age. The equivalent RI decreased with age (RI = -0.0008*age + 1.4467, p = 0.048).

Fig 2: Equivalent refractive index as a function of age. The equivalent RI decreased with age (RI = -0.0008*age + 1.4467, p = 0.048).

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